1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
10
11// <mdspan>
12
13// template<class OtherExtents>
14// constexpr explicit(!is_convertible_v<OtherExtents, extents_type>)
15// mapping(const mapping<OtherExtents>&) noexcept;
16
17// Constraints: is_constructible_v<extents_type, OtherExtents> is true.
18//
19// Preconditions: other.required_span_size() is representable as a value of type index_type
20
21#include <mdspan>
22#include <type_traits>
23#include <cassert>
24#include <limits>
25
26#include "test_macros.h"
27
28template <class To, class From>
29constexpr void test_implicit_conversion(To dest, From src) {
30 assert(dest == src);
31}
32
33template <bool implicit, class ToE, class FromE>
34constexpr void test_conversion(FromE src_exts) {
35 using To = std::layout_left::mapping<ToE>;
36 using From = std::layout_left::mapping<FromE>;
37 From src(src_exts);
38
39 ASSERT_NOEXCEPT(To(src));
40 To dest(src);
41
42 assert(dest == src);
43 if constexpr (implicit) {
44 dest = src;
45 assert(dest == src);
46 test_implicit_conversion<To, From>(src, src);
47 }
48}
49
50template <class T1, class T2>
51constexpr void test_conversion() {
52 constexpr size_t D = std::dynamic_extent;
53 constexpr bool idx_convertible =
54 static_cast<size_t>(std::numeric_limits<T1>::max()) >= static_cast<size_t>(std::numeric_limits<T2>::max());
55
56 // clang-format off
57 test_conversion<idx_convertible && true, std::extents<T1>>(std::extents<T2>());
58 test_conversion<idx_convertible && true, std::extents<T1, D>>(std::extents<T2, D>(5));
59 test_conversion<idx_convertible && false, std::extents<T1, 5>>(std::extents<T2, D>(5));
60 test_conversion<idx_convertible && true, std::extents<T1, 5>>(std::extents<T2, 5>());
61 test_conversion<idx_convertible && false, std::extents<T1, 5, D>>(std::extents<T2, D, D>(5, 5));
62 test_conversion<idx_convertible && true, std::extents<T1, D, D>>(std::extents<T2, D, D>(5, 5));
63 test_conversion<idx_convertible && true, std::extents<T1, D, D>>(std::extents<T2, D, 7>(5));
64 test_conversion<idx_convertible && true, std::extents<T1, 5, 7>>(std::extents<T2, 5, 7>());
65 test_conversion<idx_convertible && false, std::extents<T1, 5, D, 8, D, D>>(std::extents<T2, D, D, 8, 9, 1>(5, 7));
66 test_conversion<idx_convertible && true, std::extents<T1, D, D, D, D, D>>(
67 std::extents<T2, D, D, D, D, D>(5, 7, 8, 9, 1));
68 test_conversion<idx_convertible && true, std::extents<T1, D, D, 8, 9, D>>(std::extents<T2, D, 7, 8, 9, 1>(5));
69 test_conversion<idx_convertible && true, std::extents<T1, 5, 7, 8, 9, 1>>(std::extents<T2, 5, 7, 8, 9, 1>());
70 // clang-format on
71}
72
73template <class IdxT, size_t... Extents>
74using mapping_t = std::layout_left::mapping<std::extents<IdxT, Extents...>>;
75
76constexpr void test_no_implicit_conversion() {
77 constexpr size_t D = std::dynamic_extent;
78
79 // Sanity check that one static to dynamic conversion works
80 static_assert(std::is_constructible_v<mapping_t<int, D>, mapping_t<int, 5>>);
81 static_assert(std::is_convertible_v<mapping_t<int, 5>, mapping_t<int, D>>);
82
83 // Check that dynamic to static conversion only works explicitly
84 static_assert(std::is_constructible_v<mapping_t<int, 5>, mapping_t<int, D>>);
85 static_assert(!std::is_convertible_v<mapping_t<int, D>, mapping_t<int, 5>>);
86
87 // Sanity check that one static to dynamic conversion works
88 static_assert(std::is_constructible_v<mapping_t<int, D, 7>, mapping_t<int, 5, 7>>);
89 static_assert(std::is_convertible_v<mapping_t<int, 5, 7>, mapping_t<int, D, 7>>);
90
91 // Check that dynamic to static conversion only works explicitly
92 static_assert(std::is_constructible_v<mapping_t<int, 5, 7>, mapping_t<int, D, 7>>);
93 static_assert(!std::is_convertible_v<mapping_t<int, D, 7>, mapping_t<int, 5, 7>>);
94
95 // Sanity check that smaller index_type to larger index_type conversion works
96 static_assert(std::is_constructible_v<mapping_t<size_t, 5>, mapping_t<int, 5>>);
97 static_assert(std::is_convertible_v<mapping_t<int, 5>, mapping_t<size_t, 5>>);
98
99 // Check that larger index_type to smaller index_type conversion works explicitly only
100 static_assert(std::is_constructible_v<mapping_t<int, 5>, mapping_t<size_t, 5>>);
101 static_assert(!std::is_convertible_v<mapping_t<size_t, 5>, mapping_t<int, 5>>);
102}
103
104constexpr void test_rank_mismatch() {
105 constexpr size_t D = std::dynamic_extent;
106
107 static_assert(!std::is_constructible_v<mapping_t<int, D>, mapping_t<int>>);
108 static_assert(!std::is_constructible_v<mapping_t<int>, mapping_t<int, D, D>>);
109 static_assert(!std::is_constructible_v<mapping_t<int, D>, mapping_t<int, D, D>>);
110 static_assert(!std::is_constructible_v<mapping_t<int, D, D, D>, mapping_t<int, D, D>>);
111}
112
113constexpr void test_static_extent_mismatch() {
114 constexpr size_t D = std::dynamic_extent;
115
116 static_assert(!std::is_constructible_v<mapping_t<int, D, 5>, mapping_t<int, D, 4>>);
117 static_assert(!std::is_constructible_v<mapping_t<int, 5>, mapping_t<int, 4>>);
118 static_assert(!std::is_constructible_v<mapping_t<int, 5, D>, mapping_t<int, 4, D>>);
119}
120
121constexpr bool test() {
122 test_conversion<int, int>();
123 test_conversion<int, size_t>();
124 test_conversion<size_t, int>();
125 test_conversion<size_t, long>();
126 test_no_implicit_conversion();
127 test_rank_mismatch();
128 test_static_extent_mismatch();
129 return true;
130}
131
132int main(int, char**) {
133 test();
134 static_assert(test());
135 return 0;
136}
137

source code of libcxx/test/std/containers/views/mdspan/layout_left/ctor.mapping.pass.cpp